Each taken or skipped dose sent a `clear` push to every subscription of
the account. The service worker closed the pending reminder and showed
nothing. A subscription made with userVisibleOnly may not receive
pushes that show no notification: Safari revokes it after a few, the
next reminder meets a 410 and the channel is switched off, with nothing
in the app saying why.
The clear push, its three call sites and the badge count only it fed
are removed. A reminder already on screen now stays until it is tapped,
dismissed or replaced by the next reminder for the same dose. The
sender's badge field went too: nothing else ever set it. The parity
snapshots lose the two recorded effects.